The Lake Today

Missouri Department of Transportation (MoDOT) District 5 engineer Roger Schwartze said the Missouri Highways and Transportation Commission’s decision to replace rather than simply repair the 74-year-old Hurricane Deck Bridge was “extremely good news” for the Lake Area.

Schwartze said the commission made the decision during its Dec. 1 meeting because building a completely new bridge would be “the best use of transportation dollars,” when compared to making repairs to the existing bridge.

Schwartze said at best, repairing the old bridge would extend its life by another 10 years, in comparison to building a completely new structure with a life span of 75 years or more.

According to Schwartze, MoDOT had already set aside $7 million to repair the existing bridge. Because the agency had “brought a number of other road projects in under costs,” the highway commission felt it could afford the $30 million needed to build a new structure.

Earlier this year, commissioners said for at least the foreseeable future, all transportation dollars would be used to maintain current bridges and roadways and no new projects would be undertaken.

Built in 1936, the half-mile-long Hurricane Deck Bridge is of the “truss arch” design, carrying two lanes of traffic across the main channel of the Lake. The bridge sets 60-65 feet above the Lake’s surface and is the exact same design as that of the Interstate 35 Bridge that collapsed near Minneapolis, Minn., in 2007.

Schwartze said, while Hurricane Deck isn’t the only truss arch bridge still in use in Missouri, it is the only one exactly like the faultily-constructed Interstate 35 bridge in Minnesota.

Schwartze said now that the Highway Commission has given MoDOT the go-ahead to replace the Hurricane Deck Bridge, engineers would begin working on a design for the new structure as well as on how exactly the construction project would be handled.

The new bridge is to be built with two traffic lanes and shoulders wide enough to allow for pedestrians. Schwartze said when completed, the new Hurricane Deck Bridge will be at least 10 feet wider than the current structure.

“The surface of the new bridge will be a minimum of 38 feet wide instead of 28 feet like the current bridge,” Schwartze said. “That will allow for two traffic lanes, shoulders and safe walkway for pedestrians.”

He said in addition to deciding on the exact design of the new span, engineers will also determine the best way to avoid interrupting the flow of traffic on Missouri 5 while the new bridge is under construction.

He said a number of methods for dealing with the problem are under consideration, including building a new bridge alongside the current structure, then demolishing the old bridge once traffic has been rerouted across the new span.

During the past decade, MoDOT has replaced two other bridges across the Niangua Arm of the Lake (the U.S. 54 Bridge west of Camdenton and the Niangua Bridge near Greenview). In both instances, the old bridge continued to carry traffic while the new span was under construction. Also in both those projects, once traffic had been diverted to the new span, the support structure holding up the old bridge was blasted and the roadway surface allowed to fall into the Lake, where it was retrieved by cranes. Schwartze said that while engineers are looking at using that method for replacing the Hurricane Deck Bridge, they are also considering the possibility of building temporary support pilings alongside the current bridge, then “sliding the current bridge over onto those pilings” so it can serve as a “detour route” around the construction site.

“That may sound like a strange way of handling the construction,” Schwartze said. “But the engineers have some very sound reasons for wanting to use the exact footprint of the old bridge for placement of the new structure.”

Schwartze said if all goes as planned, MoDOT will be ready to advertise for contractor bids for building the $30 million structure by late December 2011 with completion of the project scheduled for 18 months beyond that.